Fluidic rectifier device



United States Patent Office 3,516,428 Patented June 23, 1970 3,516,428FLUIDIC RECTIFIER DEVICE Donald L. ReXford, Schenectady, N.Y., assignorto enlral Electric Company, a corporation of New Filed Sept. 21, 1966,Ser. No. 581,085 Int. Cl. F15c 4/00 U.S. Cl. 137-815 7 Claims ABSTRACT FTHE DISCLOSURE An analog-type fluid amplifier having the fluid receiversinterconnected in a downstream direction provides a rectification actionwherein a single polarity output is produced in phase with a bipolaritydifferentially pressurized input signal and varies proportionallytherewith. The fluid receivers are spaced apart by a center vent andthis separation dimension is critical for obtaining the most desirableinput-output wave form characteristics.

My invention relates to fluid control devices commonly described asfluid amplifiers or fluidic devices, and in particular, to a specificfluidic device which performs a rectification of input control signalswithout causing a phase inversion thereof.

One of the several basic types of fluid amplifiers is of themomentum-exchange type wherein a main or power fluid jet is deflected byone or more control jets directed laterally at the power jet fromopposite sides thereof. The power jet is normally directed midwaybetween two fluid receivers and is deflected relative thereto by anamount proportional to the net sideways momentum of the control jets.This device is thereof often referred to as a proportional or analogdevice. Various computational and control systems are known embodyinganalog-type fluid amplifiers, and one of the basic functions oftenemployed in these systems is that of rectification wherein a singlepolarity output signal is developed from a polarity input controlsignal. A fluidic device for performing a rectifier action is disclosedin a copending patent application Ser. No. 457,099, filed May 19, 1965,entitled Fluid Controls Particularly for Turbine Engines, inventorsWillis A. Boothe et al. and assigned to the assignee of the presentapplication. In such copending application, a single fluid receiver isemployed in alignment with the power nozzle which generates the powerjet. The characteristics of this fluidic rectifier device is such thatthe output pressurized fluid waveform is phase displaced from the inputdifferential pressurized control fluid waveform by 180. In many fluidiccircuits it is desirable to avoid this phase inversion between the inputand output signals.

Therefore, one of the principal objects of my invention is to provide afluidic rectifier device wherein the input and output signals are inphase.

In carrying out the objects of my invention, I provide a fluidic devicewherein the power jet is normally directed midway between two spacedfluid receivers and is controllably deflected by a pair of oppositelydisposed control fluid jets which are directed laterally at the powerjet from opposite sides thereof. The fluid receivers are incommunication with equal length fluid flow passages which areinterconnected in a downstream direction to form a common output fluidpassage wherein the downstream direction interconnection prevents freebackflow of fluid from one fluid receiving passage into the other. Thepair of fluid receivers are spaced apart and separated by a center ventpassage having an input width which is substantially equal to the widthof the power jet in order to obtain the most desirable input-outputwaveform characteristics for my rectifier device wherein a singlepolarity output pressurized fluid waveform is in phase with an inputdifferential pressurized control fluid waveform which may be ofbipolarity.

The features of my invention which I desire to protect herein arepointed out with particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation,together with further objects and advantages thereof, may best beunderstood by reference to the following description taken in connectionwith the accompanying drawing wherein:

FIG. l is a top plan view of the fluidic rectifier device constructed inaccordance with my invention; and

FIG. 2 is a graphical representation of the inputoutput characteristicsof the rectifier device.

Referring in particular to FIG. 1, there is shown a View in top plan ofa fluidic rectifier device constructed in accordance with my invention.The rectifier comprises a plurality of channels or fluid flow passagesformed in a base member or through a plurality of superposed laminates,the channels being preferably of rectangular cross section althoughother forms may also be employed and being enclosed by a suitable coverplate or plates as in conventional fluid amplifiers. The essentialelements of my fluidic rectifier device comprise a power fluid passage,a pair of control fluid passages (although a single passage may be usedif the control signal is of bipolarity), a pair of spaced fluidreceivers in communication with fluid passages interconnected in adownstream direction to form a common output fluid passage, and a centervent passage. The power fluid passage comprises a power fluid inletpassage 3 terminating in a restrictor or nozzle 4 for generating a powerjet of pressurized fluid normally directed along the center axis of thedevice midway between two spaced fluid receivers 5 and 6. The controlfluid passages comprise a pair of control fluid inlet passages 7 and 8terminating in oppositely disposed nozzles 9 and 10, respectively. Eachof the control nozzles is disposed adjacent the power nozzle 4 andsubstantially perpendicular to the power jet issuing therefrom wherebyeach control jet is directed against the side of the power jet inmomentum exchange relation. The input to power fluid inlet passage 3 isconnected to a source of substantially constant pressurized fluid bymeans of a conduit 11 extending through the cover plate of the device.The input to the control fluid inlet passages 7 and 8 is connected to adifferentially pressurized signal source in the most general casewherein such source may be the two outputs of a particular fluidamplifier device in a fluidic circuit. The connection between the inputto the control fluid inlets 7 and 8 and the source of the control fluidmay be by means of conduits 12 and 13, respectively, as illustrated, or,my rectifier device may be formed in the same base member containing thefluidic device having its output connected to the control fluid inletsof the rectifier. In such latter case, the additional conduits 12 and 13and associated fittings for connecting such conduits to the rectifierdevice input in fluid-type relationship are omitted. Fluid receiver 5 isin communication with a fluid flow passage 14, and fluid receiver 6 isin communication with a fluid flow passage 15 which passages areinterconnected at their other ends in a downstream direction to form acommon output fluid flow passage 16. The downstream direction connectionprevents free back flow of fluid from one fluid receiving passage intothe other. Receivers S and 6 are of equal width in the most general caseand are spaced apart by a width greater than the width of the power jetin the region of the receivers. The separation between fluid receivers 5and 6 contains the inlet to a center vent passage 22 which, though notby way of limitation 3 but in order to obtain the best operation of mydevice, has an input width substantially equal to the width of the powerjet and greater than either receiver width. Center vent passage 22 hasits outlet end extending through the cover plate and in communicationwith the ambient atmosphere as indicated by circular opening 23.Alternatively, passage 22 may be utilized as a center output to obtainthe second side of a push-pull output signal in combination withreceivers 5 and 6. A conduit 17 is in communication with passage 16 andextends through the cover plate to provide the outlet of my rectifierdevice. Fluid passages 14 and 15 are of equal length to avoid any phasedisplacement between the flows in the respective passages. The passagesshould also be of minimum length to reduce the time constant of therectifier.

A pair of side vent passages 18 and 19 are preferably employed torelieve fluid pressure in the receivers resulting from unusual loadingconditions, although my device is operable without these side vents. The-vent passages 18 and 19 are disposed adjacent receivers S and 6,respectively, on opposite sides of the power jet. The outer ends of thevent passages 18 and 19 extend through the cover plate and are incommunication with the ambient atmosphere as indicated by circularopenings 20 and 21.

The operating characteristics of my rectifier device are illustrated inFIG. 2 which is a graphical representation of the output fluid pressurein pounds per square inch gauge-p.s.i.g. (measured in conduit 17) as afunction of the input differential control fluid pressure measuredbetween conduits 12 and 13. These input-output characteristicsillustrate the particular advantage of my device wherein the outputpressure waveform is in phase with the input control pressure waveform.Thus, it can be seen that the output pressure is a direct function ofthe magnitude of input differential control pressure and is alsoindependent of the direction or polarity of the input differentialcontrol pressure. The curves in FIG. 2 identified by the letters a and bwere obtained in tests of a fluidic rectifier device constructed inaccordance with my invention wherein the power nozzle had a width of0.040 inch, each of the receivers had a width of 0.040 inch, the centervent passage inlet had a width of 0.080 inch and the spacing between thetip of the power nozzle and the inlet to the center vent passage was0.270 inch. 'Ihe tests were conducted at a power fluid supply pressureof l p.s.i.g. Curves a and b were both obtained with the center ventpassage being unrestricted, that is, opening 23 being open to theatmosphere. The unrestricted condition of the center vent passageobtains the best operating characteristics in that a minimum outputfluid pressure is obtained for the condition of zero differentialcontrol fluid pressure (zero point) and the curve has a relatively sharpbottom at this zero point. Curve a was obtained with the output inconduit 17 being blocked, that is, a no load condition whereas curve bwas obtained with a 0.020 inch diameter orifice inserted into conduit 17as a load. It was found that the addition of a load to the center ventincreased the output fluid pressure at the zero point. Also, the spacingof receivers 5 and 6 further apart obtains a more shallow bottom curveat the zero point as indicated by dashed line c. The wider receiverspacing also decreases the output pressure at the zero point by a smallamount. A spacing of the receivers closer than illustrated in FIG. lincreases the output pressure at the zero point and also reduces thegain, that is, the slope of the curve in the normal operating range. Thereceiver spacing for the rectifier device illustrated in FIG. 1 isoptimized as evidenced by the curves a and b wherein a higher gain overa relatively large portion of the curve is obtained as compared to thegain obtained with curves for closer or wider receiver spacings andthere also exists a relatively sharp bottom characteristic at the zeropoint.

My rectifier device has good operating characteristics over a powerfluid supply pressure range of at least 1 to 15 p.s.i.g. Operation ofthe device at power supply pressures considerably below or above thisrange would require a change in the ratio of the dimensions (powernozzle width, receiver width, center vent width, power nozzle to centervent) which are illustrated in the FIG. 1 plan view.

It is apparent from the foregoing that my invention attains theobjectives set forth. In particular, my invention makes available alluidic rectifier device wherein the output signal is in phase with theinput control signal as distinguished from a prior rectifier devicewherein such signals are phase displaced by The desirable inputoutputcharacteristics of my rectifier device are obtained by spacing the fluidreceivers further apart than in conventional analog-type fluid amplifierdevices and by interconnecting the fluid receiving passages in adownstream direction to form a common output fluid passage.

Having described an embodiment of my fluidic rectifier device, it isbelieved obvious that modification andvariation of my invention ispossible in the light of the above teachings. Thus, although the ratioof the dimensions illustrated in FIG. 1 provide a rectifier with manygood characteristics, the pair of fluid receivers can be further spacedapart or spaced closer together, or the power nozzle to center ventspacing changed in order to obtain other specific characteristics, asdesired. Further, it is to be understood that a single control fluidinlet passage terminating in a nozzle may be employed in place of thetwo passages and nozzles, and this arrangement obtains thecharacteristics of the FIG. 2 graph if the pressures of the controlfluid signal vary above and below ambient or atmospheric pressure, i.e.are of bipolarity. Finally, it is recognized that the control means forcontrollably defiecting the power jet is not limited tothe use ofpressurized control fluid jets, but may also include other known meansemployed in the fluid amplifier art.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An analog-type fluidic rectifier device comprising firstmeans forgenerating a jet of pressurized fluid,

a pair of spaced fluid receivers downstream from said first means forreceiving pressurized fluid from a jet generated by said first means,

, said pair of fluid receivers spaced apart by the inlet to a firstfluid passage means disposed therebetween, the width of the inlet tosaid first fluid passage means being substantially twice as great as thewidth of either of said pair of receivers for obtaining optimumoperating characteristics of said device,

analog-type control means for controllably deflecting the jet generatedby said first means relative to said spaced receivers in a proportionalmanner, and

second fluid passage means directly connected to said receivers forinterconnecting said spaced receivers whereby the pressure of the fluidat the output of said second fluid passage means is independent of thedirection of deflection of the jet generated by said first means and isproportionally directly related to the magnitude of the control exertedby said control means -to thereby provide the characteristics of arectifier wherein the output fluid pressure is in phase with the controlexerted by said control means and varies proportionally therewith over aparticular operating range of said control means.

2. The fluidic rectifier device set forth in claim 1 wherein saidcontrol means comprises a pair of control fluid inlet passagesterminating in oppositely disposed nozzles for generating oppositelydirected control jets of proportionally varying pressurized fluid inintercepting relationship to the jet generated -by said first means,Ithe output fluid pressure varying proportionally with the pressure ofthe control jets over a particular operating range of control fiuidpressures. 3. The fiuidic rectifier device set forth in claim 1 whereinsaid first fluid passage means is aligned with the axis of said firstmeans for generating a jet of fluid.

4. The uidic rectifier device set forth in claim 1 wherein the width ofthe inlet to said first fluid passage means is substantially equal tothe width of the power jet thereat whose fiuid is distributed betweensaid first fiuid passage means and one of said receivers over theparticular operating range of said control means. 5. The fiuidicrectifier device set forth in claim 1 wherein said second fluid passagemeans comprise a first fluid passage directly connected to a first ofsaid pair of receivers and a second uid passage directly connected `to asecond of said pair of receivers, said first and second fluid passagesinterconnected in a downstream direction to form a common output fluidpassage wherein the downstream direction interconnection prevents freeback flow of fluid from one fluid receiving passage to the other. 6. Thefiuidic rectifier device set forth in claim 5 wherein said first andsecond fluid passages are of equal length. 7. The fluidic rectifierdevice set forth in claim 1 wherein said pair of spaced fluid receiversare each of equal width.

References Cited UNITED STATES PATENTS 3,411,520 ll/l968 Bowles 137-8153,192,938 7/1965 Bauer 137-815 3,266,509 8/1966 Bauer 137--815 3,340,8859/1967 Bauer 137-815 SAMUEL SCOTT, Primary Examiner

